Evaporative Cooling Applied in Thermal Power Plants:A Review of the State-ofthe-Art and Typical Case Studies

A review is conducted about the application of the evaporative cooling technology in thermal power plants.Different case studies are considered,namely,evaporative air conditioners,evaporative cooling in direct air-cooled systems,gas turbine inlet cooling,wet cooling towers,and hybrid cooling towers with a crosswind effect.Some effort is provided to describe the advantages related to direct evaporative cooling when it is applied in thermal power plants and illustrate the research gaps,which have not been filled yet.In particular,typical case studies are intentionally used to compare the cooling performances when direct evaporative cooling is implemented in different types of cooling towers,including the natural draft wet cooling tower(NDWCT)and the pre-cooled natural draft dry cooling tower(NDDCT).It is shown that the NDWCT provides the best cooling performance in terms of power station cooling,followed by the pre-cooled NDDCT,and the NDDCT;moreover,the evaporative pre-cooling is able to enhance the cooling performance of NDDCT.Besides,on a yearly basis,better NDDCT cooling performances can be obtained by means of a spray-based pre-cooling approach with respect to wet media pre-cooling.Therefore,the use of nozzle spray is suggested for improvement in the performance of indirect/direct air-cooling systems with controlled water consumption.

Probabilistic Approach of Coastal Defense Against Typhoon Attacks for Nuclear Power Plant

With the global warming and sea level rising, it is widely recognized that there is an increasing tendency of typhoon occurrence frequency and intensity. The defenses code against typhoon attacks for nuclear power plant should be calibrated because of the increasing threat of typhoon disaster and severe consequences. This paper discusses the probabilistic approach of definitions about ＂probable maximum typhoon＂ and ＂probable maximum storm surge＂ in nuclear safety regulations of China and has made some design code calibrations by use of a newly proposed Double Layer Nested Mtdti-objective Probability Model （DLNMPM）.

Forced Compressed Air Cooling System for a 300 MW Steam Turbine in Waigaoqiao Power Plant

The 300 MW steam turbine installed in Waigaoqiao Power Plant with combined HPIP cylinders of double casing structure is a product of the Shanghai Turbine Works utilizing licensed technology. It has a large heat storage capacity and good thermal insulation, so the metal temperature of first stage of HP cylinder (FSMTI) may reach 400-450℃ after shut down and it takes 7-8 days to cool to 150℃ by natural cooling, Now with a forced cooling system the cooling time may be reduced to 40 hours, so that the turbine may be opened for repair work in about 5-6 days. The cooling system for #2 unit and test procedure are briefly described below.

The Experimental Investigation of Recirculation of Air-Cooled System for a Large Power Plant

The paper introduces thermal buoyancy effects to experimental investigation of wind tunnel simulation on direct air-cooled condenser for a large power plant. In order to get thermal flow field of air-cooled tower, PIV experiments are carried out and recirculation ratio of each condition is calculated. Results show that the thermal flow field of the cooling tower has great influence on the recirculation under the cooling tower. Ameliorating the thermal flow field of the cooling tower can reduce the recirculation under the cooling tower and improve the efficiency of air-cooled condenser also.

Choice of Site for the Installation of Photovoltaic Solar Power Plants in Senegal: Consequences on Electricity Production

A theoretical analysis of the electricity production of a photovoltaic solar power plant of 22 MW for different sites in Senegal is presented. The study is carried out in two coastal regions (Dakar and Saint-Louis) and two continental regions (Mbacké and Linguère). This study is done using the RET Screen clean energy project management software climate data. The amount of electricity exported to the grid is calculated for each site. The results show that the climatic conditions of the coastal and continental regions are different from November to June. From July to October, which corresponds to the rainy season in Senegal, the climatic conditions of the coastal and continental regions are similar. The results also show that although the efficiency of photovoltaic modules is better on the coast, electricity production varies little from one site to another. Climate conditions in Senegal therefore have no impact on electricity production.

Modeling the Effect of Thermal Diffusion Process from Nuclear Power Plants in Vietnam

In this study, we evaluate the ecological impact of effluent cooling water from the Ninh Thuan nuclear power plant II, using a two-dimensional hydraulic model to simulate thermal diffusion from the effluent outfall. Sites selected for this study were Ninh Thuan nuclear power plant and Vinh Hai seawater in four different scenarios. This paper utilized the relationship between surface water temperature and the water temperature at a depth of -15 m to calculate the water temperature at intake and outlet at a depth of -14 m. A combination between the results of interpolated and results of model showed that effluent cooling water from Ninh Thuan plant affected the largest incidence about 2450 m in the North, 880 m in the South and 960 m in the West. It can be considered as safe distance to not to affect the coral reefs ecosystem in the North and sea turtle conservation area in the South. This study was first in this region to have an integrated approach using two-dimensional model.

Zooplankton community size-structure change and mesh size selection under the thermal stress caused by a power plant in a semi-enclosed bay

Zooplankton samples were collected using 505, 160 and 77 μm mesh nets around a power plant during four seasons in 2011. We measured total length of zooplankton and divided zooplankton into seven size classes in order to explore how zooplankton community size-structure might be altered by thermal discharge from power plant. The total length of zooplankton varied from 93.7 to 40 074.7 μm. The spatial distribution of mesozooplankton(200-2 000 μm) populations were rarely affected by thermal discharge, while macro-(2 000-10 000 μm)and megalo-zooplankton(>10 000 μm) had an obvious tendency to migrate away from the outfall of power plant.Thus, zooplankton community tended to become smaller and biodiversity reduced close to power plant.Moreover, we compared the zooplankton communities in three different mesh size nets. Species richness,abundance, evenness index and Shannon-Wiener diversity index of the 505 μm mesh size were significantly lower than those recorded from the 160 and 77 μm mesh size. Average zooplankton abundance was highest in the 77 μm mesh net((27 690.0±1 633.7) ind./m^3), followed by 160 μm mesh net((9 531.1±1 079.5) ind./m^3), and lowest in 505 μm mesh net((494.4±104.7) ind./m^3). The ANOSIM and SIMPER tests confirmed that these differences were mainly due to small zooplankton and early developmental stages of zooplankton. It is the first time to use the 77 μm mesh net to sample zooplankton in such an environment. The 77 μm mesh net had the overwhelming abundance of the copepod genus Oithona, as an order of magnitude greater than recorded for 160 μm mesh net and 100% loss through the 505 μm mesh net. These results indicate that the use of a small or even multiple sampling net is necessary to accurately quantify entire zooplankton community around coastal power plant.

A New Water Saving Device of Swirling Flow for Cooling Towers

This paper is concerned with water saving for water-loop cooling tower system in power plants. A newly developed water saving device of swirling flow is presented. The key point is that the new water saving device makes the steam swirl up along the device wall rather than engender laminar flow in a corrugated plate. The corrugated plate device can save approximately 10 percent of the total lost water. In contrast to the scale model of corrugated plate water saving device, experimental analyses have demonstrated that the new water saving device of swirling flow is more efficient, with a capacity of saving more than 20 percent of water.

电化学循环水阻垢技术在电力行业的应用展望

在工业发展中,循环冷却水的结垢问题一直备受关注,有效的阻垢技术对降低生产能耗和减少水资源的浪费具有重要意义。电化学阻垢技术因具有高效、无需投加药剂、同步杀菌等优点受到了广泛的关注。从电化学阻垢技术的发展、原理以及实际应用等方面,综述了电化学阻垢技术在循环冷却水处理中的应用情况并展望了在电力行业冷却水处理中的应用前景。包括以时间为向导结合文献计量学可视化分析,比较了近十年阻垢技术相关研究热点;进一步从电化学阻垢技术的简介、与传统阻垢技术的比较、研究现状以及影响因素出发,并结合实际应用情况,提出了电化学阻垢技术尚且存在的困难和挑战,最后对电化学阻垢技术在电力行业中的应用前景进行了展望。

凉水塔变形监测与基坑敏感因子灰色关联分析

基坑开挖容易引起临近电厂凉水塔变形,是深基坑工程面临的主要难题之一。本文实地监测深基坑开挖对附近电厂凉水塔的影响,统计了基坑开挖过程中凉水塔地表垂直和水平位移、结构变形等参数。依托某实际工程,研究基坑开挖引起凉水塔变形预测方法,建立凉水塔地表垂直位移灰色预测模型。采用灰色关联分析确定基坑各敏感因素对凉水塔变形的影响程度,由大到小依次为:基坑与建筑物间距、土体弹性模量、围护结构厚度、土体内摩擦角、土体粘聚力。通过开展凉水塔变形监测与相关研究工作,相关研究理论能够为类似深基坑工程提供参考。

大型直流冷却火电厂用水特征分析

直流冷却火电厂是我国工业用水大户,随着水资源短缺问题日益严重、节水要求日益提高,开展直流冷却火电厂用水特征分析研究,为节水改造提供技术支撑,愈发紧迫。文章以中山嘉明电厂为例,对其开展水平衡测试工作,确定电厂用水结构,推演用水参数及各系统用水指标,进行节水潜力分析并提出节水措施。分析结果显示,直流冷却是该类电厂主要的用水、退水环节,电厂用水指标满足相关定额要求,但在除盐水回用等方面仍有一定的节水潜力。测试及分析的开展为大型直流冷却火电行业节水改造、节水企业创建提供了一定的参考和借鉴。

发电厂冷却工艺用水发展现状与展望

冷却工艺用水是发电厂总用水量的主要部分。随着全球淡水资源持续紧缺,改进冷却工艺系统、提高冷却水使用效率的必要性和迫切性日益凸显。从多个方面对发电厂冷却工艺节约用水进行了论述,概述了现有冷却工艺的局限性;介绍了对发电厂冷却系统进行改进和优化以实现节水、降耗的新工艺;探讨了以海水和再生水为代表的非传统水源应用于冷却系统的可能性,以及将其应用于冷却工艺时可能面临的复杂性和挑战;介绍了冷却水处理和水质监测的关键技术,阐述了相关技术改进所能带来的节水效果;最后提出了冷却水管理方面存在的机遇与挑战。

2023年冬季宁德核电冷源海域棘头梅童鱼(Collichthys lucidus)资源声学评估

滨海核电厂冷却水源的取水安全正受到海洋生物暴发引起的堵塞威胁,鱼类堵塞核电冷源的事件时有发生。声学技术在海洋生物探测方面具有高效、实时的优势,因此,被广泛应用于海洋生态系统研究。为了解冬季宁德核电厂冷却水源取水海域棘头梅童鱼(Collichthys lucidus)的密度和运动规律,利用声学技术对相关海域冷却水源生物量进行了测量和评估。研究结果显示,棘头梅童鱼为研究海域的优势种,拖网调查显示平均尾数密度为1964尾·km^(-2),平均质量密度为0.483 kg·km^(-2)。棘头梅童鱼丰度在研究海域向核电厂方向减少,质量密度以核电厂温排水区域站点最高。通过对鱼类回波特征和个体轨迹的追踪统计,分析了该海域冬季内单体目标强度检测及其空间结构分布、资源现存量和资源丰度密度的时空分布变化。声学走航海域鱼类平均密度为2.78×10^(5)尾·n mile^(-2),生物量密度均值为1.41×10^(4) kg·n mile^(-2),棘头梅童鱼资源总量为7.47×10^(5) kg。研究表明,声学技术在宁德核电厂取水海域冬季冷却水源生物量测量中具有明显优势。通过不断改进和优化方法,声学技术将能更好地支持核电厂取水海域的生态环境监测与资源管理,为冷却水源取水安全提供科学依据。

火电厂源侧综合能源系统集成及性能评估研究

本文建立了以火电厂为核心,消纳可再生能源并提供冷热电汽综合能源服务的一套能源系统,通过对整体系统及关键子系统热力性能分析,验证了提出模型和方法的有效性。并研究了一些关键运行参数对系统综合性能的影响,验证了提出模型和方法的有效性和优越性。结果表明:通过改变火电厂的源侧参数,可以提高综合能源系统荷侧的输出量;且生物质转化气对汽轮机发电功率的影响最大。热泵系统的负荷随着进入系统中的给水流量的增大而增大,利用汽轮机中的部分抽汽来驱动热泵系统,虽然发电功率下降了10.88%,但是却为用户提供了16.8MW的热负荷和16.2MW的冷负荷以及27.78t/h的蒸汽量。

基于相变蓄冷的核电厂主控室非能动冷却系统

为提高现有核电厂主控室紧急可居留系统的蓄冷能力及热舒适性水平,提出了基于定形相变蓄冷材料的核电厂主控室非能动冷却系统。基于主控室热负荷分布情况,该冷却系统在主控室顶板与吊顶之间、内墙面、地板底面及循环风道内,针对性地布置相应的含有定形相变材料的非能动冷却装置,进而实现事故工况下对主控室温度的精确控制。该非能动冷却系统无需引入额外冷源和管道,可靠性强,同时不破坏主体结构,且可灵活布置,解决了现有主控室非能动热阱时间余量小、热舒适性差的问题。

滨海火电厂循环水管道硫化氢气体的产生、危害及预防措施

滨海火电厂循环水管道中硫化氢等有毒有害气体的积累不仅会影响冷却系统的正常运行,还会对周边环境及现场作业人员的健康造成严重危害,是困扰火电厂安全运行的重大难题.因此,研究火电厂循环水管道中硫化氢的产生机制并针对性提出防控措施,是火电厂亟需解决的科学问题.基于此,本文从滨海火电厂循环水管道中如何产生硫化氢及防治的科学问题出发,介绍了硫化氢对环境、设备和人员的严重危害,综述了不同自然环境中硫化氢产生的机制,指出了微生物介导硫酸盐还原作用是循环水管道中硫化氢产生的关键,并根据国内外研究进展对硫化氢的防治策略进行了展望.本文对于科学防控火电厂循环水管道产生硫化氢等有毒有害气体的风险具有重要的指导意义.

基于CFD的阀门保温层传热仿真分析

非能动二次侧余热排出(PRS)系统的蒸汽管道与主蒸汽管道相连,给水管线与PRS系统凝水管线相连。在开展系统热工流体分析时发现,若非能动二次侧余热排出系统蒸汽管线与二回路主蒸汽管线之间的蒸汽隔离阀常开,高温蒸汽直接作用于阀门,加上保温层的作用阻碍阀门散热,可能会导致蒸汽隔离阀内部温度过高,引起阀门电装无法正常动作。本文计算分析了PRS系统蒸汽隔离阀带保温层状态下的传热情况,判断阀门在高温流体下是否能保证电机的可用性。

基于热泵技术的余热回收供热系统

传统热电厂的循环冷却水中含有大量的低品位余热,利用热泵技术对其进行回收,能够显著提升供热系统的能源利用效率,有利于实现节能减排和“碳中和”目标。设计基于单、双吸收式热泵机组的余热回收供热系统,旨在有效利用循环冷却水中的余热,增加供热能力并分析系统性能。结果表明,与传统供热系统相比,两种余热回收供热系统均可显著回收循环冷却水的热量,提高系统供热量并大幅减少能源消耗,带来可观的经济收益;双吸收式热泵机组系统展现出更优异的热力性能,具备显著的节能减排优势。分析循环冷却水入口温度和一次网回水温度对双吸收式热泵机组性能的影响,发现循环冷却水温度对系统性能影响较大,随着循环冷却水温度的升高,系统的供热量增加比例、节约标煤量和新增供热面积均增加,而一次网回水温度对系统性能的影响较小,随一次网回水温度的升高,系统的供热量增加比例、节约标准煤量和新增供热面积几乎不变。

火电厂排污水处理系统RO膜污染成因分析及处理

某火电厂循环冷却排污水经净化处理后再次回用,但净化处理系统反渗透(RO)膜单元运行中出现故障,存在反渗透段间压差快速上升,产水率和脱盐率下降等现象,通过对反渗透进水水质分析、循环冷却系统水源变化分析、膜元件标准测试、膜元件解剖、膜片染色试验、污染物灼烧失重分析和污染物成分鉴定等工作分析RO膜单元运行故障原因。结果表明,采用城市中水作为循环冷却系统补水后,经循环冷却系统浓缩后的排污水中有机物、钙镁离子、磷酸根离子和碱度等含量偏高,是造成反渗透膜污堵的主要原因,膜污染物以磷酸盐无机污垢为主要成分,有机污垢为次要成分,同时伴随硅垢、铁垢等污垢物。采取增加碱加药装置和非氧化杀菌剂加药装置、修复硫酸加药装置、对现有反渗透膜进行彻底离线化学清洗等措施,使反渗透系统恢复正常运行,有效解决了运行中反渗透膜频繁污堵问题。

电站仪用压缩空气供应系统冷却塔防冻措施优化

针对田湾核电站二期工程仪用压缩空气供应系统的冷却塔防冻问题,通过梳理系统流程、冷却塔工作原理及其防冻措施,结合现场发生的防冻问题,提出一系列优化措施。研究结果表明,通过完善设备保温、优化防冻回路逻辑、改进设备防风措施和紧急情况下的运行干预策略,可以有效降低仪用压缩空气供应系统因冰冻导致的不可用风险,从而确保核电站的安全稳定运行。